Design

Bob Tarr's Design Patterns
Gives an introduction to design patterns and their importance in software design.
http://www.cetus-links.org/oo_patterns.html

Chris Ruel's Object Technology Website
This website explores software engineering utilizing the principles of object technology and design patterns to achieve methodical and consistent software designs.
http://eyebright.sslnetworks.org/~chrisrue/ChrisRuel.net/ChrisRuelNet.htm

John R. Harris | Virtual Travelog
Site of a System Architect with ideas / opinions, mostly regarding system design.
http://www.virtualtravelog.net/

Refactoring Home Page
Refactoring is a technique to restructure code in a disciplined way. It is useful for improving the design of existing code.
http://www.refactoring.com/

Software Information
Basic introductory information regarding the development of software. Seems to be targeted towards novices.
http://www.softinfo.20m.com/

Whiteboard Modeling Tips and Techniques
Whiteboards are the most common modeling tool in use today. This essay explores how to model effectively on a whiteboard.
http://www.agilemodeling.com/essays/whiteboards.htm